The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 16, 1999
Filed:
Jun. 19, 1997
Zahir Ebrahim, Mountain View, CA (US);
Sun Microsystems, Inc., Mountain View, CA (US);
Abstract
A low overhead, efficient, and simple protection check circuit is inserted into a data path between a master requester and a target resource such as a memory or input/output device. The master requester initiates a memory request, a pio access request, or a dma transaction directed to the target resource. For example, the master requester may be a processor accessing a memory, a processor performing programmed I/O (pio). Alternatively, the master requester may be a DMA device performing direct memory access of a memory. The protection check circuit is configured at initialization time by an operating system or a privileged software process, then passively monitors all transactions on the data paths, disallowing accesses that fail the protection check operation.